Hemming finishing punch, robot including hemming finishing punch, and hemming finishing processing method

ABSTRACT

Provided is a finishing processing method, including placing an inner panel having a protrusion and an outer panel on each other, and, by using a hemming finishing punch having an arc-shaped pressing surface and having a relief hole of a size corresponding to the protrusion at a central part of the pressing surface, pressing the outer panel so that the arc-shaped pressing surface is rolled along an end portion of the outer panel and the relief hole corresponds to the protrusion.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Japanese Patent Application No. 2018-199723 filed with the Japan Patent Office on Oct. 24, 2018, the entire content of which is hereby incorporated by reference.

BACKGROUND 1. Technical Field

An embodiment of the present disclosure relates to a hemming finishing punch, a robot including this hemming finishing punch, and a hemming finishing processing method.

2. Related Art

Regarding vehicle doors, a single product is generally formed by joining, through a hemming process, two panel members, i.e., an inner panel and an outer panel that have been processed into predetermined shapes in advance. The hemming process is a process in which both the panels are fixed to each other by bending an end portion of the outer panel so as to sandwich an end portion of the inner panel. In order to secure this fixation, a part subjected to the hemming process is subjected to spot welding in many cases. Spot welding can further improve bond strength between the inner panel and the outer panel.

In order to securely perform spot welding, a protrusion is formed in advance on a part of the inner panel to be subjected to spot welding. Then, the hemming process is performed so that the end portion of the outer panel abuts against this protrusion. Thereafter, spot welding is performed. Thus, a welding current is concentrated on the protrusion. Therefore, the inner panel and the outer panel are favorably melted in the vicinity of the protrusion. This makes it possible to secure welding strength.

In this case, a desired effect cannot be obtained if the protrusion of the inner panel is crushed in the hemming process. Therefore, the hemming process is desirably performed so as not to crush the protrusion, and the hemming process is also desirably performed so that the outer panel has a shape matched with a shape of the protrusion.

In a case where a desired roller hemming process is performed by a roller, in a process of a part in the vicinity of the protrusion, pressing force of the roller is generally adjusted so as not to crush the protrusion. In this state, the hemming process is performed on the whole circumferences of the panel members. In this case, in the vicinity of the protrusion, a press using the roller is merely such a press that the inner panel abuts against the outer panel. Therefore, close contact between the end portion of the outer panel and the inner panel is incomplete. Thus, in a case where spot welding is performed in this state, spattering tends to occur and quality of appearance tends to be deteriorated when spot welding is performed.

Therefore, in some cases, the part in the vicinity of the protrusion is subjected to a finishing process after the hemming process by using a punch having a relief hole corresponding to the protrusion at a central part thereof. In this case, however, it is necessary to match a shape of a pressing surface of the punch with a shape of a design surface of the part. Thus, it is necessary to prepare a dedicated punch for each protrusion.

Further, in order to prevent the protrusion from being crushed, there is proposed a method of performing a roller hemming process by using a roller having a circular recess at a central part thereof (see JP-A-2007-237283). The hemming process is performed by this roller on the circumferences of the panels in a first direction so that the circular recess of the roller passes above the protrusion. Thereafter, the hemming process is performed in a direction crossing the first direction. In this way, the hemming process is performed in the vicinity of the protrusion without crushing the protrusion (see FIG. 6).

In the above hemming system, the hemming process is performed by using the roller having a circular recess at a central part thereof. Therefore, pressing pressure is hardly applied to the central part that is regarded as an important part to secure quality. This may deteriorate processing quality.

SUMMARY

A hemming finishing punch according to an embodiment of the present disclosure has an arc-shaped pressing surface for pressing an outer panel placed on an inner panel, and a relief hole of a size corresponding to a protrusion of the inner panel at a central part of the pressing surface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a door inner panel and a door outer panel according to this embodiment;

FIG. 2 is a front view illustrating a state in which a hemming finishing punch according to this embodiment is provided on a robot;

FIG. 3 is a cross-sectional side view, including the relief hole, of the hemming finishing punch according to this embodiment and illustrates a state in which the hemming finishing punch abuts against a part in the vicinity of a protrusion and starts pressing;

FIG. 4 is a cross-sectional side view, including the relief hole, of the hemming finishing punch according to this embodiment and illustrates a state in which the hemming finishing punch presses a protrusion;

FIG. 5 is a cross-sectional side view, including the relief hole, of the hemming finishing punch according to this embodiment and illustrates a state in which the hemming finishing punch is further rolled (a state in which a process is completed) from a state in which the hemming finishing punch presses a protrusion; and

FIG. 6 illustrates an aspect of a hemming process using a roller having a circular recess at a central part thereof, the roller being disclosed in JP-A-2007-237283.

DETAILED DESCRIPTION

In the following detailed description, for purpose of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.

An object of the present disclosure is to perform a hemming process of a part in the vicinity of a protrusion set in an inner panel in a short time while restraining crush of the protrusion and securing quality of the hemming process.

A hemming finishing punch (a present hemming finishing punch) according to an embodiment of the present disclosure has an arc-shaped pressing surface for pressing an outer panel placed on an inner panel, and a relief hole of a size corresponding to a protrusion of the inner panel at a central part of the pressing surface.

By rolling the arc-shaped pressing surface, a part in the vicinity of the protrusion which has not been subjected to a hemming process with high pressure can be continuously pressed from an end of the pressing surface. A press using a substantially flat pressing surface is a simple flat press from a single direction. Therefore, it is necessary to form a punch for each protrusion in accordance with a shape of a curved surface in the vicinity of the protrusion. On the contrary, the present hemming finishing punch is configured so that the arc-shaped pressing surface is rolled to perform a line contact press. Therefore, it is possible to perform a process by using a common punch.

Further, the relief hole of the size corresponding to the protrusion is provided at the central part of the pressing surface. With this, it is possible to restrain pressing force from being applied to the protrusion.

A robot (present robot) according to an aspect of the present disclosure includes the present hemming finishing punch (the present hemming finishing punch is provided on the robot).

The present robot includes, for example, a robot hand, and the present hemming finishing punch is provided on the robot hand. With this, by programming the present robot to perform operation by teaching, the present robot can continuously perform a finishing process of a plurality of protrusions. As a result, it is possible to reduce performance time of this step.

The present robot may further include a hemming roller. In this case, the hemming finishing punch may be provided to be adjacent to the hemming roller.

With this configuration, the hemming finishing punch is provided to be adjacent to the hemming roller. With this, the present robot can perform a hemming finishing process by using the hemming finishing punch immediately after the roller hemming process is terminated. This makes it possible to reduce performance time of this step.

A finishing processing method according to an embodiment of the present disclosure (a present finishing processing method) includes placing an inner panel having a protrusion and an outer panel on each other, and, by using a hemming finishing punch having an arc-shaped pressing surface and having a relief hole of a size corresponding to the protrusion at a central part of the pressing surface, pressing the outer panel so that the arc-shaped pressing surface is rolled along an end portion of the outer panel and the relief hole corresponds to the protrusion.

In the present finishing processing method, as well as in the present hemming finishing punch, by rolling the arc-shaped pressing surface, a surface (part) in the vicinity of the protrusion which has not been subjected to a hemming process with high pressure can be continuously pressed from an end of the pressing surface. A press using a substantially flat pressing surface is a simple flat press. Therefore, it is necessary to form punches for the number of protrusions in accordance with shapes of curved surfaces in the vicinity of the protrusions. On the contrary, in the present finishing processing method, the arc-shaped pressing surface is rolled to perform a line contact press. Therefore, it is possible to perform a process by using a common punch. Further, the relief hole of the size corresponding to the protrusion is provided at the central part of the pressing surface. With this, it is possible to restrain pressing force from being applied to the protrusion.

In the present finishing processing method, the hemming finishing punch may be provided on a robot hand of a robot, and the press may be performed by operation of the robot.

Because the hemming finishing punch is provided on the robot hand, by programming the robot including the robot hand to perform operation by teaching, a finishing process of a plurality of protrusions can be continuously performed by operation of the robot. This makes it possible to reduce performance time of this step.

According to the present hemming finishing punch, a high-quality hemming finishing process can be performed by the following uniform operation: the present hemming finishing punch is rolled while pressing each of the protrusions. This makes it possible to reduce time taken for this step.

The foregoing detailed description has been presented for the purposes of illustration and description. Many modifications and variations are possible in light of the above teaching. It is not intended to be exhaustive or to limit the subject matter described herein to the precise form disclosed. Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of performing the claims appended hereto.

Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Note that the following description of the embodiment is merely an essential example. The following description is not intended to limit a technique of the present disclosure, an application thereof, or use thereof.

In a hemming process of a door, a protrusion is provided in an inner panel in order to secure joining, and, after the hemming process, an electrode is put on the protrusion and spot welding is performed. As illustrated in FIG. 1, for example, three protrusions 13 are provided on a front side of a front door according to this embodiment. Further, two protrusions 13 are provided on a rear side thereof. Each protrusion 13 is subjected to spot welding after the hemming process.

Further, in this embodiment, the inner panel and an outer panel are subjected to a roller hemming process by using a hemming process roller. Specifically, an end portion of the outer panel, which has been subjected to a flanging process in a preceding step, is further bent by the hemming process roller and is processed to sandwich an end portion of the inner panel. In this way, the hemming process is performed. At this time, the hemming process is performed so that the protrusions 13 of an outer panel 12 are restrained from being crushed. This is because, if the protrusions 13 are crushed, a desired effect of concentrating a current cannot be obtained at the time of spot welding, and it is difficult to secure quality of the spot welding. Therefore, when parts in the vicinity of the protrusions 13 are subjected to roller hemming, for example, pressing force of the roller is reduced to restrain the protrusions 13 from being crushed.

Steps of the roller hemming process will be described. In the preceding step, the end portion of the molded outer panel 12 is subjected to the flanging process at an angle of approximately 90°. First, the outer panel 12 and an inner panel 11 molded in the same way as the outer panel are placed on each other in corresponding postures. Then, the roller hemming process is performed at an angle of approximately 45° on the whole circumference of the end portion of the outer panel 12 subjected to the flanging process. This is a step called “preliminary bending”.

Then, the end portion of the outer panel 12 is bent by the roller until the end portion is brought into close contact with the inner panel 11. This is a step called “final bending”. At this time, if the final bending is performed on the whole circumference, the protrusions 13 are crushed. Therefore, in parts corresponding to the protrusions 13 (parts in the vicinity of the protrusions 13), the process is performed so that pressing force is adjusted to restrain the protrusions 13 from being deformed and, in addition, the outer panel 12 abuts against tops of the protrusions 13 of the inner panel 11.

As a result, at the time the roller hemming process is finished on the whole circumference, a hemming process is completed almost on the whole circumference, leaving only the outer panel 12 in the vicinity of the protrusions 13 processed to abut against the protrusions 13. That is, in the vicinity of the protrusions 13, the roller presses merely to the extent that the outer panel 12 abuts against the protrusions 13 of the inner panel 11. Therefore, in the vicinity of the protrusions 13, close contact between the end portion of the outer panel 12 and the inner panel 11 is incomplete. Thus, in a case where spot welding is performed in this state, spattering tends to occur and quality of appearance tends to be deteriorated when the spot welding is performed.

Therefore, in many cases, the parts in the vicinity of the protrusions 13 are subjected to a finishing process before the spot welding is performed. This finishing process conventionally includes, for example, a press using a finishing punch having a flat pressing surface. In many cases, however, the parts in the vicinity of the protrusions 13 are formed as curved surfaces according to a design of the door. Further, the shapes of those curved surfaces vary by position. Therefore, dedicated hemming finishing punches having shapes matched with shapes of the curved surfaces have been used for the respective protrusions.

On the contrary, in this embodiment, the hemming finishing punch has a pressing surface configured to be arc-shaped. With this, when a press is performed by the hemming finishing punch, the pressing force is applied to a line defining the designed surfaces. Therefore, as being rolled and pressing, the hemming finishing punch is adaptable to any of the curved surfaces having different shapes. Thus, a single hemming finishing punch can be used regardless of the shapes of the surfaces to be pressed.

In this embodiment, a curvature of the arc shape of the pressing surface of the hemming finishing punch is R75 as illustrated in FIG. 3. As a result of performing trial and error while changing a magnitude of a curvature R, it is determined that appropriate magnitude of the curvature R falls within a range of R60 to R90. In a case where the curvature R is smaller than R60, a posture of the hemming finishing punch is largely changed when the protrusions 13 are subjected to the finishing process by using the hemming finishing punch. Thus, a possibility of occurrence of interference or the like between a robot on which the hemming finishing punch is provided and another apparatus is increased. Meanwhile, in a case where the curvature R is larger than R90, there is not much difference from a case of using a hemming finishing punch having a flat pressing surface. Therefore, a press using the hemming finishing punch is susceptible to an influence of shapes of the parts in the vicinity of the protrusions 13.

Further, as illustrated in FIG. 2, in a robot (robot hand) according to this embodiment, a punch support portion 3 is attached to a roller support portion 22 to be adjacent to a roller 23 that is a hemming roller (roller for hemming). Specifically, as illustrated in FIG. 3, the punch support portion 3 is fastened to the roller support portion 22 with bolts. This structure has the following advantage: after a roller hemming step is terminated, a finishing step of the hemming process using the finishing punch can be immediately started by operation of the same robot, that is, performance time for those steps can be reduced.

Specific operation will be described with reference to FIGS. 3 to 5. First, as illustrated in FIGS. 3 and 4, a finishing punch (hemming finishing punch) 1 is caused to abut against the outer panel 12 by operation of the robot hand included in the robot so that a peripheral part of the protrusion 13 is pressed by a peripheral part of the arc-shaped pressing surface. Then, the pressing surface 2 is operated by the robot hand so that an arc-shaped pressing surface 2 of the finishing punch 1 is rolled along the end portion of the outer panel 12 and a relief hole 6 provided in the pressing surface 2 corresponds to the protrusion. With this operation, the peripheral part of the protrusion 13 in which close contact in the hemming process is incomplete is pressed by the finishing punch 1. With this, as illustrated in FIGS. 4 and 5, a state of close contact between the outer panel 12 and the inner panel 11 is achieved, and the hemming process of the protrusion 13 and the peripheral part thereof is completed. This finishing process is performed with respect to all the protrusions 13 of the inner panel, i.e., the five protrusions 13 in this embodiment. Thus, the finishing hemming step is terminated. By teaching this series of operation to the robot in advance, it is possible to automatically perform the finishing process of each protrusion.

By causing an electrode to abut against a part on the outer panel 12 side of each protrusion 13 in this state and performing spot welding, a welding current concentratedly flows into a part of the protrusion 13 between the outer panel 12 and the inner panel 11. As a result, this part is sufficiently heated and is favorably melted. Therefore, high-quality welding is performed.

Note that the embodiment of the present disclosure may be the following first to third hemming finishing punches and first and second finishing processing methods.

A first hemming finishing punch is a hemming finishing punch that is used for a finishing process of a part in the vicinity of a protrusion that an inner panel has when an end portion of an outer panel is bent to sandwich the inner panel and a hemming process is performed, in which a pressing surface has an arc shape and has a relief hole of a size corresponding to the protrusion at a central part of the pressing surface.

A second hemming finishing punch is the first hemming finishing punch and is provided on a robot hand.

A third hemming finishing punch is the second hemming finishing punch and is provided to be adjacent to a hemming roller.

A first finishing processing method is a finishing processing method of a part in the vicinity of a protrusion that an inner panel has, which is used when an end portion of an outer panel is bent to sandwich the inner panel and a hemming process is performed, in which, by a hemming finishing punch having an arc-shaped pressing surface and having a relief hole of a size corresponding to the protrusion at a central part of the pressing surface, the outer panel is pressed so that the arc-shaped pressing surface is rolled along the end portion and the relief hole corresponds to the protrusion.

The second finishing processing method is the first finishing processing method, in which the hemming finishing punch is provided on a robot hand, and the press is performed by operation of a robot. 

What is claimed is:
 1. A hemming finishing punch having an arc-shaped pressing surface for pressing an outer panel placed on an inner panel, and having a relief hole of a size corresponding to a protrusion of the inner panel at a central part of the pressing surface.
 2. A robot, comprising the hemming finishing punch according to claim
 1. 3. The robot according to claim 2, further comprising a hemming roller, wherein the hemming finishing punch is provided to be adjacent to the hemming roller.
 4. A finishing processing method, comprising: placing an inner panel having a protrusion and an outer panel on each other; and by using a hemming finishing punch having an arc-shaped pressing surface and having a relief hole of a size corresponding to the protrusion at a central part of the pressing surface, pressing the outer panel so that the arc-shaped pressing surface is rolled along an end portion of the outer panel and the relief hole corresponds to the protrusion.
 5. The finishing processing method according to claim 4, wherein the hemming finishing punch is provided on a robot hand of a robot, and the press is performed by operation of the robot. 